Posterior psoas vs 3-in-1 approach for lateral femoral cutaneous and obturator nerve block for anterior cruciate ligament repair.

AIM: The aim of this article was to test the hypothesis that the posterior psoas compartment approach to the lumbar plexus help to achieve better blockade of the lateral femoral cutaneous and obturator nerves than the classic anterior 3-in-1 femoral nerve block. METHODS: Thirty-six patients who were undergoing anterior cruciate ligament repair were randomly allocated to receive a femoral nerve block using either an anterior 3-in-1 femoral block (group Femoral, N=18) or a posterior psoas compartment approach (group Psoas, N=18) using 30 mL of 1.5% mepivacaine. Successful nerve block was defined as a complete loss of pinprick sensation in the region that is supplied by the lateral femoral cutaneous nerve along with adequate motor block of the obturator nerve 30 minutes after injection. The degree of motor block of the obturator nerve was measured using adduction strength with a mercury sphygmomanometer as previously described by Lang. RESULTS: Thirty minutes after the completion of the block, sensory block of the lateral femoral cutaneous nerve was observed in 14 patients (78%) from the Psoas group and in 3 patients (17%) from the Femoral group (P=0.001). Thirty minutes after the completion of the block, a 119+/-40 mmHg decrease was found in Psoas group, in contrast to the 25+/-22 mmHg decrease found in the Femoral group (P<0.0005). CONCLUSIONS: The posterior psoas compartment approach provides a more reliable block of the lateral femoral cutaneous and obturator nerves than the anterior 3-in-1 approach.

Prospective clinical evaluation of 1920 Morse taper connection implants: results after 4 years of functional loading.

PURPOSE: This study evaluated the survival rate and the clinical, radiographic and prosthetic success of 1920 Morse taper connection implants. MATERIAL AND METHODS: One thousand nine hundred and twenty Morse taper connection implants were inserted in 689 consecutive patients, from January 2003 until December 2006. Implants were clinically and radiographically evaluated at 12, 24, 36 and 48 months after insertion (mean follow-up per implant: 25.42 months). Modified plaque index (mPI), modified sulcus bleeding index, probing depth (PD) and the distance between implant shoulder and first crestal bone-implant contact (DIB) were measured in mm. Success criteria included the absence of suppuration and clinically detectable implant mobility, PD<5 mm, DIB<1.5 mm after 12 months of functional loading and not exceeding 0.2 mm for each following year, the absence of recurrent prosthetic complications at the implant-abutment interface. Prosthetic restorations were fixed partial prostheses (364 units), single crowns (SCs: 307 units), fixed full-arch prostheses (53 units) and overdentures (67 units). RESULTS: The overall cumulative implant survival rate was 97.56% (96.12% in the maxilla and 98.91% in the mandible). The cumulative implant success rate was 96.61% (95.25% in the maxilla and 98.64% in the mandible). Only a few prosthetic complications were reported (0.65% of loosening at implant-abutment interface in SCs). CONCLUSION: The use of Morse taper connection implants represents a successful procedure for the rehabilitation of partially and completely edentulous arches. The absence of an implant-abutment interface (microgap) is associated with minimal crestal bone loss. The high mechanical stability significantly reduces prosthetic complications.

Effect of nitrous oxide on desflurane MACBAR at two target-controlled concentrations of remifentanil.

BACKGROUND: The aim of this prospective, randomized, double-blind study was to determine the effect of nitrous oxide on the desflurane requirement for blunting sympathetic response following surgical incision (MACBAR) when desflurane was combined with two different target-controlled concentrations of remifentanil (1 and 3 ng/mL). METHODS: A total of 103 patients, aged 20-50 years, ASA physical status I, scheduled to undergo general anesthesia for elective abdominal surgery, were randomly allocated to receive anesthesia with desflurane alone (Group A, n = 53), or with the addition of 60% nitrous oxide (Group N, n = 50). Patients of both groups were further assigned to receive a target-controlled plasma concentration of 1 ng/mL (Group A1, n = 27; Group N1, n = 26) or 3 ng/mL remifentanil (Group A3, n = 26, Group N3, n = 24). Sympathetic responses to surgical incision were determined after a 20 min period of constant end-tidal desflurane and target-controlled remifentanil concentrations. Predetermined end-tidal desflurane concentrations and the MACBAR for each group were determined using an up-and-down sequential allocation technique. RESULTS: A total of 98 patients completed the study. The MACBAR of desflurane was 5.2% (95% confidence interval [CI95: 4.9-5.5%]) in Group A1 and 2.7% (CI95: 2.6-2.8%) in Group N1 (P<0.001), while in Groups A3 and N3 the MACBAR of desflurane was 2.2% (CI95:2-2.4%) and 2% (CI95:1.9-2.2%), respectively (P<0.01). When considering a minimum anesthetic concentration (MAC) value with a contribution of 60% nitrous oxide (0.55 MAC) in this population, the combined MACBAR values (expressed as multiples of the MAC) were 1.9 MAC for group A1, 1 MAC for group N1, 0.8 MAC for group A3, and 0.7 MAC for group N3. CONCLUSION: The addition of 60% nitrous oxide reduces the MACBAR of desflurane by 52% when using a remifentanil concentration of 1 ng/mL, and reduces the MACBAR by 10% when using a remifentanil concentration of 3 ng/mL.

Faster wash-out and recovery for desflurane vs sevoflurane in morbidly obese patients when no premedication is used.

BACKGROUND: The aim of this study was to compare desflurane vs sevoflurane kinetics and dynamics in morbidly obese patients and their recovery profile when no premedication had been used. METHODS: Twenty-eight unpremedicated obese patients were randomly allocated to receive either sevoflurane (n = 14) or desflurane (n = 14) as the main anaesthetic agent. After induction of anaesthesia, either sevoflurane 2% or desflurane 6% was administered for 30 min via a non-rebreathing circuit. The kinetics of sevoflurane and desflurane were determined by measuring and recording end-tidal samples during this time. The bispectral index was used to indicate the level of hypnosis. At the end of the procedure, the end-tidal concentrations of sevoflurane and desflurane were recorded during the first 5 min after stopping their administration. Time from discontinuation of the anaesthetic drugs to eye opening on verbal command, squeezing the observer's hand on command, extubation, stating their name, giving their correct date of birth, discharge from the recovery room, and duration of the surgery and anaesthesia were also recorded. RESULTS: The F(A)/F(I) ratio was significantly higher in the desflurane group from the 15th to the 30th min. The wash-out phase was faster for desflurane during the total observation period. When desflurane was used, recovery was also faster. CONCLUSIONS: Desflurane provides faster wash-in and wash-out than sevoflurane in morbidly obese patients, and recovery is much faster after desflurane administration when no premedication has been used.

The use of propofol and remifentanil for the anaesthetic management of a super-obese patient.

Morbid obesity is defined as body mass index (BMI) > 35 kg.m(-2), and super-obesity as BMI > 55 kg.m(-2). We report the case of a 290-kg super-obese patient scheduled for open bariatric surgery. A propofol-remifentanil TCI (target controlled infusion) was chosen as the anaesthetic technique both for sedation during awake fibreoptic nasotracheal intubation and for maintenance of anaesthesia during surgery. Servin's weight correction formula was used for propofol. Arterial blood samples were taken at fixed time points to assess the predictive performance of the TCI system. A significant difference between measured and predicted plasma propofol concentrations was found. After performing a computer simulation, we found that predictive performance would have improved significantly if we had used an unadjusted pharmacokinetic set. However, in conclusion (despite the differences between measured and predicted plasma propofol concentrations), the use of a propofol-remifentanil TCI technique both for sedation during awake fibreoptic intubation and for Bispectral Index-guided propofol-remifentanil anaesthesia resulted in a rapid and effective induction, and operative stability and a rapid emergence, allowing rapid extubation in the operating room and an uneventful recovery.

Effect of morbid obesity on kinetic of desflurane: wash-in wash-out curves and recovery times.

AIM: The aim of this paper was to compare wash-in and wash-out curves of desflurane in morbidly obese and nonobese patients. METHODS: Fourteen patients (7 obese and 7 nonobese) were studied. In the nonobese patients, anaesthesia was started by administering 2 mg/kg propofol bolus and a target controlled effect site concentration of remifentanil set at 2.5 ng/mL. Obese patients were intubated using a flexible fiberoptic bronchoscopic technique facilitated by a target controlled effect site concentration of remifentanil set at 2.5 ng/mL. After endotracheal intubation, general anaesthesia was started by administering a 1.5 mg/kg propofol bolus dose. Ten minutes after induction of anaesthesia, 4% desflurane was administered for 30 min. Desflurane kinetics was determined by collecting end-tidal samples from first breaths at 1, 5, 10, 15, 20, 25 and 30 min. At last skin suture, the end-tidal concentration of desflurane was recorded from 5 consecutive breaths before their discontinuation, then the end-tidal samples of the inhalational agent were collected at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 and 5 min after terminating its administration. The period of time from discontinuation of desflurane to opening eyes, squeezing the observer's hand, extubation, stating the patients' name and providing date of birth was also recorded. RESULTS: The FA/FI ratio was higher in the nonobese group from the 10th to the 15th min. Wash-out curves of desflurane and recovery times were similar. CONCLUSION: Our results show that desflurane provides similar kinetic and recovery profiles in obese and nonobese patients.

Predictive performance of 'Servin's formula' during BIS-guided propofol-remifentanil target-controlled infusion in morbidly obese patients.

BACKGROUND: The aim of this study was to assess the predictive performance of 'Servin's formula' for bispectral index (BIS)-guided propofol-remifentanil target-controlled infusion (TCI) in morbidly obese patients. METHODS: Twenty patients (ASA physical status II-III, age 32-64 yr) undergoing bilio-intestinal bypass surgery, were recruited. Anaesthesia was induced by using a TCI of propofol with an initial target plasma concentration of 6 microg ml(-1), then adapted to maintain stable BIS values ranging between 40 and 50. A TCI of remifentanil was added to achieve pain control and haemodynamic stability. For propofol, weight was corrected as suggested by Servin and colleagues. With ideal body weight (IBW) corrected according to formula suggested by Lemmens and colleagues. For remifentanil, weight was corrected according to IBW. Arterial blood samples for the determination of blood propofol concentrations were collected at different surgical times. The predictive performance of propofol TCI was evaluated by examining performance accuracy. RESULTS: Median prediction error and median absolute prediction error were -32.6% (range -53.4%; -2.5%) and 33.1% (10.8%; 53.4%), respectively. Wobble median value was 5.9% (2.5%; 25.2%) while divergence median value was -1.5% h(-1) (-7.7; 33.8% h(-1)). CONCLUSION: Significant bias between predicted and measured plasma propofol concentrations was found while the low wobble values suggest that propofol TCI system is able to maintain stable drug concentrations over time. As already suggested before, a computer simulation confirmed that the TCI system performance could be significantly improved when total body weight is used.

Effect site concentrations of remifentanil maintaining cardiovascular homeostasis in response to surgical stimuli during bispectral index guided propofol anestesia in seriously obese patients.

AIM: The aim of this prospective study was to determine the effect site concentrations of remifentanil maintaining cardiovascular homeostasis in response to surgical stimuli during bispectral index (BIS) guided propofol anesthesia in seriously obese patients. METHODS: Twenty-two patients, female/male 15/7, ASA physical status II - III, aged 29-69 years, body mass index (BMI) 54.5+/-12, undergoing major open bariatric surgery, were enrolled to receive a propofol-remifentanil total intravenous anesthesia. All patients were intubated by using a flexible fiberoptic bronchoscopic technique facilitated by a target controlled effect site concentration of remifentanil set at 2.5 ng/mL. After endotracheal intubation, anesthesia was started with a target controlled infusion of propofol initially set at 6 microg/mL, then adjusted to maintain a BIS value between 40 and 50. The mean effect site concentration of remifentanil was recorded at different intervals time during surgery: skin incision-opening of peritoneum (T1), bowel resection (T2), cholecystojejunal anastomosis (T3), ileojejunal anastomosis (T4), closing of peritoneum (T5). RESULTS: The mean plasma concentrations of propofol required to maintain a BIS value between 40 and 50 were 4+/-0.55, 3.8+/-0.64, 3.8+/- 0.63, 3.8+/-0.65 and 3.8+/-0.63 microg/mL at T1, T2, T3, T4 and T5 interval time, respectively. The mean values of remifentanil target effect site concentration were 5.2+/-1.3, 7.7+/-1.7, 9.1+/-1.8, 9.7+/- 2.2 and 9.9+/-2.5 ng/mL at T1, T2, T3, T4 and T5 interval time. CONCLUSIONS: This study suggests that tolerance to remifentanil infusion is profound and develops very rapidly in morbidly obese patients submitted to open bariatric surgery during BIS guided propofol anesthesia. The administration of opiates during anesthesia based on target-controlled infusion should include corrections for the development of tolerance.